Most non-invasive blood pressure units generally include a blood pressure cuff that can be wrapped around a patient's limb over an artery. Blood pressure readings are typically obtained by initially inflating the cuff to a pressure that is high enough to constrict the flow of blood through the artery and the pressure in the cuff is then reduced under controlled conditions. Because the patient's heart is pumping blood through the constrained artery, the cuff pressure which is typically measured by a pressure sensor will include pressure changes produced by the blood flow which are superimposed upon the changing cuff pressure as the cuff is being deflated so that both a patient's systolic and diastolic blood pressure can be determined.
Systolic pressure is the maximum arterial pressure that is produced during contraction of the left ventricle of the heart. Diastolic pressure is the minimum arterial pressure that occurs during relaxation and dilation of the heart ventricles during which time the ventricles are filling with blood. Using the well known oscillometric method, the blood pressure cuff is initially inflated to a pressure that is greater than the highest expected systolic reading. The cuff is then deflated to a pressure that is less than the expected diastolic pressure. Above the systolic pressure, the pressure sensor readings reflect only the cuff pressure. When the cuff pressure falls to the systolic blood pressure level, the pressure signals indicate the presence of oscillations which are now superimposed upon the falling cuff pressure. When the cuff pressure falls below the diastolic pressure, the oscillations are no longer present on the cuff pressure signals. These two events can thus be recorded and further processed to provide valuable information concerning the condition of a patient's heart and his or her general health.
In many health care facilities, such as a doctor office, a single non-invasive blood pressure cuff may sometimes be used on a large number of patients during the day before the cuff is sanitized. Accordingly, cross contamination between ill patients can occur. In many other health care facilities, particularly where many of the patient's are confined to bed, the blood pressure units are mounted upon mobile carriages that can be transported between patient locations. Typically the various system components that are mounted upon the carriage are interconnected by lengthy electrical wires and pneumatic tubes. These connections invariably become entangled and pose a hazard to both health care workers and patients alike.